Regulatory Assets and Liabilities - Summary of Regulatory Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Regulatory Assets and Liabilities [Line Items]
Total regulatory assets, net	$ 311,525	$ 307,374
Postretirement costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	17,399	19,387
Financing costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	7,935	8,279
Fair value of long-term debt
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	127,977	138,701
Debt issuance costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	5,665	6,252
TCJA
Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities	(375,000)	(375,000)	$ (348,600)
CLECO POWER
Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities	(4,700)
Regulatory assets	1,000
Total regulatory assets, net	152,549	134,755
CLECO POWER | Mining costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	0	1,274
CLECO POWER | Interest costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	3,958	4,208
CLECO POWER | AROs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	3,668	3,099
CLECO POWER | Postretirement costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	151,543	140,245
CLECO POWER | Tree trimming costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	11,341	9,069
CLECO POWER | Training costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 6,241	6,396
REMAINING RECOVERY PERIOD (YRS.)	40 years
CLECO POWER | Surcredits, net
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 145	289
CLECO POWER | AMI deferred revenue requirement
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 3,136	3,681
REMAINING RECOVERY PERIOD (YRS.)	6 years
CLECO POWER | Emergency declarations
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 1,349	2,980
CLECO POWER | Production operations and maintenance expenses
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	7,985	12,245
CLECO POWER | AFUDC equity gross-up
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	72,766	71,952
CLECO POWER | Acquisition costs or Transaction costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 2,124	2,230
REMAINING RECOVERY PERIOD (YRS.)	20 years
CLECO POWER | Acquisition costs or Transaction costs | Natural Gas Processing Plant
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 906	938
REMAINING RECOVERY PERIOD (YRS.)	29 years 6 months
CLECO POWER | Financing costs
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	$ 7,554	7,923
CLECO POWER | Corporate franchise tax, net
Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities	(1,145)
Regulatory assets		1,416
CLECO POWER | Non-service cost of postretirement benefits
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	6,739	4,629
CLECO POWER | Energy efficiency
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	2,820	2,585
CLECO POWER | Accumulated deferred fuel
Regulatory Assets and Liabilities [Line Items]
Regulatory assets	22,910	20,112
CLECO POWER | Other, net
Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities	(4,543)	(4,979)
CLECO POWER | Total regulatory (liabilities) assets — deferred taxes, net
Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities	$ (146,948)	$ (155,537)